Thermal-Emission Properties of La-W、Ce-W、Y-W Electrode Materials

The influence of rare-earth oxide La₂O₃, Ceo₂ and Y₂O₃ on the emission ability and stability of tungsten electrode materials were investigated. Three new kinds of RE-W electrode materials were produced by powder metallurgy and metal processing technology. They were compared with one another in respect of the arc starting characterstics and the arc voltage-current characteristics. The La-W, Ce-W, Y-W, and Th-W cathode tip microstructure after arc burning were observed through SEM and EDAX. The action of rare-earth elements and their acting mechanism in the emission process of tungsten electrode. As it turned out that the La₂O₃-W electrode. of which w(La₂O₃)=2.2% exhibited the best properties when the current is of little or middle volume, and when the cathodes are used in large current, the Y₂O₃-W electrode is the best.